BACKGROUND:Coronary artery anomalies (CAAs) are currently undergoing profound changes in understanding potentially pathophysiological mechanisms of disease. Aim of this study was to investigate the prevalence of anomalous origin and course of coronary arteries in consecutive symptomatic patients, who underwent cardiac 64-slice multidetector-row computed tomography angiography (MDCTA).METHODS:Imaging datasets of 748 consecutive symptomatic patients referred for cardiac MDCTA were analyzed and CAAs of origin and further vessel course were grouped according to a recently suggested classification scheme by Angelini et al.RESULTS:An overall of 17/748 patients (2.3%) showed CAA of origin and further vessel course. According to aforementioned classification scheme no Subgroup 1- (absent left main trunk) and Subgroup 2- (anomalous location of coronary ostium within aortic root or near proper aortic sinus of Valsalva) CAA were found. Subgroup 3 (anomalous location of coronary ostium outside normal "coronary" aortic sinuses) consisted of one patient with high anterior origin of both coronary arteries. The remaining 16 patients showed a coronary ostium at improper sinus (Subgroup 4). Latter group was subdivided into a right coronary artery arising from left anterior sinus with separate ostium (subgroup 4a; n = 7) and common ostium with left main coronary artery (subgroup 4b; n = 1). Subgroup 4c consisted of one patient with a single coronary artery arising from the right anterior sinus (RAS) without left circumflex coronary artery (LCX). In subgroup 4d, LCX arose from RAS (n = 7).CONCLUSIONS:Prevalence of CAA of origin and further vessel course in a symptomatic consecutive patient population was similar to large angiographic series, although these patients do not reflect general population. However, our study supports the use of 64-slice MDCTA for the identification and definition of CAA.

Published: I I December 2009 Received: 6 August 2009
BMC Cardiovascular Disorders 2009, 9:54 doi: 10.1186/1471-2261-9-54 Accepted: II December 2009
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Abstract
Background: Coronary artery anomalies (CAAs) are currently undergoing profound changes in
understanding potentially pathophysiological mechanisms of disease. Aim of this study was to
investigate the prevalence of anomalous origin and course of coronary arteries in consecutive
symptomatic patients, who underwent cardiac 64-slice multidetector-row computed tomography
angiography (MDCTA).
Methods: Imaging datasets of 748 consecutive symptomatic patients referred for cardiac MDCTA
were analyzed and CAAs of origin and further vessel course were grouped according to a recently
suggested classification scheme by Angelini et al.
Results: An overall of 17/748 patients (2.3%) showed CAA of origin and further vessel course.
According to aforementioned classification scheme no Subgroup I (absent left main trunk) and
Subgroup 2- (anomalous location of coronary ostium within aortic root or near proper aortic sinus
of Valsalva) CAA were found. Subgroup 3 (anomalous location of coronary ostium outside normal
"coronary" aortic sinuses) consisted of one patient with high anterior origin of both coronary
arteries. The remaining 16 patients showed a coronary ostium at improper sinus (Subgroup 4).
Latter group was subdivided into a right coronary artery arising from left anterior sinus with
separate ostium (subgroup 4a; n = 7) and common ostium with left main coronary artery (subgroup
4b; n = I). Subgroup 4c consisted of one patient with a single coronary artery arising from the right
anterior sinus (RAS) without left circumflex coronary artery (LCX). In subgroup 4d, LCX arose
from RAS (n = 7).
Conclusions: Prevalence of CAA of origin and further vessel course in a symptomatic consecutive
patient population was similar to large angiographic series, although these patients do not reflect

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general population. However, our study supports the use of 64-slice MDCTA for the identification
and definition of CAA.

Background
Coronary artery anomalies (CAAs) are still topic of
intense discussions. This diverse group of congenital dis-
orders is likely to show a broad variability of clinical man-
ifestations as well as pathophysiological mechanisms of
disease [ 1-3 ]. Diagnosis of CAA is usually established dur-
ing invasive coronary angiography (ICA). However, due
to the two-dimensional projectional nature of ICA, the
visualization of a complex three-dimensional vessel
course as well as clarification of the exact relationship to
surrounding anatomical structures may be difficult and
misinterpretation is reported in up to 50% of the cases
[4,5]. Recent technical developments in contrast-
enhanced cardiac multidetector row computed tomogra-
phy angiography (MDCTA) introducing faster scanners
currently provide non-invasive three-dimensional imag-
ing of coronary arteries. Besides a high diagnostic accuracy
for the detection of significant coronary heart disease
(CHD), current guidelines suggest usefulness of this diag-
nostic imaging modality for the evaluation of aberrant
coronary vessel courses [6]. Multiple studies throughout
the years have shown that MDCTA even with older scan-
ner technology is a reliable non-invasive technique to
identify CAAs and define their further course [7-10].
Although CAAs lack clinical significance in the majority of
these patients, certain anomalous patterns, like anoma-
lous origin of a coronary vessel from the opposite sinus
have been associated with sudden cardiac death and
ischemic complications [ 1,11]. For the evaluation of prev-
alence and clinical characteristics as well as for compari-
son of different imaging modalities, an exact definition of
CAAs is mandatory. Classification criteria for CAAs have
been extensively discussed in literature, but to date no
general accepted classification scheme exists. In a recent
publication a comprehensive and systematic approach on
anatomical patterns has been proposed by Angelini [12].
The lack of such a strict terminology in current literature
may partly explain the differences in reported prevalence
ranging from 0.3% in necropsy studies up to 5.64% in a
cineangiogram evaluation of 1,950 patients [11,13-18].
Aim of this study was to investigate the prevalence of CAA
in consecutive symptomatic patients, who underwent car-
diac 64-slice multidetector-row computed tomography
angiography (MDCTA) by applying this suggested classifi-
cation scheme for comparability reasons. This study
focuses only on anomalies of origin and further vessel
course. Myocardial bridges which are surely present in
more than 1% of the general population suggest that this

may be a normal variant and were therefore not included
[12,19].

Methods
Patients
Between November 2005 and February 2007, a total
number of 748 (389 male, 359 female, mean age: 47.0 +
12.3 years, age range: 8-85 years) consecutive sympto-
matic patients were referred to the University of Florida,
Department of Radiology, Shands, Jacksonville for cardiac
MDCTA due to suspicion or assumed progression of
CHD. Within these patients all datasets were reviewed in
search of coronary anomalies of origin and further vessel
course. General exclusion criteria for MDCTA according to
the hospitals clinical practice were 1) unstable clinical
conditions and inability to perform a short 10- to 15-sec-
ond breathhold; 2) severe cardiac arrhythmias prior to the
scan (e.g. bigeminy, trigeminy, and atrial fibrillation)
known to cause severe image artifacts in MDCTA; 3) con-
traindications for a betablocker treatment, such as severe
atrio-ventricular conduction blockage; 4) elevated serum
markers suggesting myocardial infarction (Troponin); 5)
renal function impairment (serum creatinine >1.5 mg/dl);
and 6) known allergy to radiographic contrast media
without a previous prophylactic medical treatment. Data
analysis was approved by the institutional review board
and patients gave written informed consent.

For MDCTA a 64-slice scanner (Sensation 64 Cardiac, Sie-
mens Healthcare, Malvern, PA) was used. A native, pro-
spectively ECG-triggered scan for coronary artery calcium
scoring (CS) was performed first, followed by a contrast-
enhanced, retrospectively ECG-gated coronary MDCTA
scan. For CS tube voltage was 120 kV at a current of 200
mAs. The MDCTA scan protocol included a tube voltage
of 120 kV at a current of 850 mAs 950 mAs. Pitch was
0.2. Gantry rotation was 330 ms with the use of a halfscan
algorithm for image reconstruction. Bolus tracking in the

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ascending aorta at a threshold of 100 HU was performed
for timing. An overall of 100 ml of contrast agent (Iopro-
mide, Ultravist 370 mgl/ml, Berlex, Montville, NJ) was
used intravenously at a flow-rate of 5 ml/s. Out of these
initially obtained raw-data sets, standardized image
reconstruction according to the hospitals practice were
performed at 25%, 45%, and 65% of the RR-Interval,
respectively and therefore, no ECG-triggered tube modu-
lation was used for data acquisition. If necessary, addi-
tional reconstructions throughout the whole cardiac cycle
were made. For image reconstruction a slice thickness of
0.75 mm with an increment of 0.5 was chosen and a
medium smooth body kernel (B25f) was applied. Addi-
tionally, average radiation exposure (MDCTA and CS) was
estimated using the individual dose length product (DLP)
given in the scan protocol multiplied by 0.017 mSv mGy-
1 cm-1 (i.e. region-specific normalized effective dose coef-
ficient for chest examinations in MDCT) as suggested by
the European Guidelines on Quality Criteria for Com-
puted Tomography [20].

mens Healthcare, Malvern, PA). Maximum Intensity
Projections (MIPs), curved Multiplanar Reformats
(cMPRs), and Volume Rendering Technique (VRT) were
performed by experienced radiologists to evaluate coro-
nary arteries. In agreement with Angelini, nature and
name of a specific coronary artery was assigned not
according to the site of origin or proximal course, but
according to the dependent myocardial territory [21].
Thereby, as the right coronary artery (RCA), the vessel pro-
viding blood flow to the right ventricular wall and as the
left anterior descending coronary artery (LAD), the vessel
supplying the anterior interventricular septum was
defined. The left circumflex artery (LCX) feeds the free
wall of the left ventricle on the obtuse margin of the heart.
Coronary anomalies were classified depending on anom-
alies of origin and further vessel course [12]. Thereby the
following types were subdivided if existing: a) Absence of
left main trunk, i.e. a split origination of the left main cor-
onary artery and the left circumflex ramus (Subgroup 1);
b) anomalous location of the coronary ostium within the
aortic root or near proper sinus of Valsalva (Subgroup 2);
c) anomalous location outside "normal" coronary ostium
(Subgroup 3); and d) anomalous location of the coronary
ostium at improper sinus of Valsalva, which may involve

Statistical analysis
All statistical analyses were performed using the MedCalc
software package (MedCalc Software; Version 7.0.0.4;
Mariakerke; Belgium) on a desktop computer. To com-
pare ages of male and female an unpaired Wilcoxon-Test
(Mann-Whitney) was used. All numbers are given in
mean + standard deviation. Calculations were considered
to be significant at a p-value of< 0.05.

According to the proposed classification scheme [12] with
respect to anomalies of origin and further vessel course,
an overall of two main types of CAAs were described and
grouped under aforementioned classification scheme (see
Table 2).

No patient with a Subgroup 1 (Absence of left main
trunk) or Subgroup 2-CAA was found.

In 1/748 patients (0.1%) a complex anomalous coronary
anatomy was investigated. Thereby inter-arterial (between
aorta and pulmonary artery) and intramural courses for
both left main coronary artery (LM) and RCA with a

somewhat anterior position of the RCA-ostium within the
right sinus of Valsalva was noted (see Figure 1; Subgroup
3). Further vessel course was unremarkable. This patient
has had history of syncope related to exercise without
chest-pain. Elevated cardiac enzymes (Troponin) raised
suspicion of myocardial ischemia. A previous ICA con-
firmed an existing CAA. MDCTA was ordered for pre-sur-
gical planning.

The remaining 16/748 patients (2.1%) were noted to
present anomalous locations of the coronary orifices at
improper sinuses (Subgroup 4). For a detailed overview,
see Table 2.

In 8 patients (1.1%) the RCA arose from the opposite
sinus of Valsalva with a separate ostium for RCA and LM
in 7 cases (Subgroup 4a; 0.9%, Figure 2) and a common
ostium of RCA and LM (single coronary artery) in one case
(Subgroup 4b; 0.1%; see Figure 3). All of them (5 male; 3
female) experienced symptoms of chest pain and showed
proximal intramural courses of the RCA, but with unre-
markable termination. Mean age was 41.5 + 18.0 years
(range: 17-73 years). An overall of 4 patients already were
diagnosed as having CAAs, either with previous out-clinic
ICA (n = 2) or echocardiography (n = 2).

One patient (Subgroup 4c; 0.1%; 58 year old male) had
an anomalous origination of LM from the opposite sinus
together with RCA (common ostium; single coronary
artery) as depicted in Figure 4. Additionally the proximal
part of the left anterior descending coronary artery (LAD)
was noted to course intramyocardially ("myocardial
bridge"). Termination was found to be normal. Small cor-
onary calcifications were present in proximal parts of the
RCA. This patient also complained of chest pain and a pre-
vious out-clinic ICA verified the existence of a CAA and
furthermore non-stenotic CHD. The indication for cardiac
MDCTA in this specific case was ruling out of progression
of CHD and further clarification of anatomical relation-
ships.

The remaining 7 patients (6 male; 1 female) showed an
abnormal origin of LCX from the right sinus of Valsalva
with a further posterior course within the atrioventricular
groove (Subgroup 4d; 0.9%; see Figure 5). In latter cases
no additional anomalous courses of LAD were depicted.
Termination of LCX was normal in all patients. Coronary
calcifications were present in an overall of 4 patients.

Discussion
According to the current literature, CAAs occur in roughly
1% of the general population. This prevalence is derived
from ICA studies performed for suspected CHD [14-
16,18]. Necropsy studies report even lower numbers:
Alexander and Griffith [13] observed only 54 CAAs in

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Table 2: Results for detected coronary artery anomalies

Subgroup I: Absent left main trunk (split origination of LCA); not found

Subgroup 2: Anomalous location of coronary ostium within aortic root or near proper aortic sinus of Valsalva (for each artery); not found

18,950 cases (0.3%). These studies are limited by entry ograms [11]. Thereby the authors reported a prevalence
bias and lack of clear diagnostic criteria, which both are for CAAs of 5.6%, which is higher than the usually cited
prerequisites for defining the true prevalence in a general prevalence derived from angiographic reports, but compa-
population. The first study adopting strict criteria for rable to one of the first reports using 64-slice CT in a
assessing CAAs was done by Angelini and co-workers, somehow similar approach. In this study the authors
They prospectively analyzed 1,950 consecutive cineangi- report a prevalence of coronary anomalies of origin and

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Figure I
High origin of the left and anterior origin of the right coronary artery (Subgroup 3). In this complex case a high ori-
gin of LM above the commissure between right and left coronary sinuses within the aortic root was reported. Furthermore
RCA originates in a somewhat anterior position. Image A (Volume Rendering Technique) depicts the acute angle of LM (white
arrow) above the aortic cusp (grey arrow), which is suspected as a possible mechanism of ischemia. In image B the close prox-
imity of both coronary ostia in ICA is shown. Curved Multiplan Reformatting (Image C) displays further proximal course of LM
and RCA between aorta and pulmonary artery. Note the ovoid cross sections of both intramural courses (cross-sectional
images of RCA and LM), which is suspicious of lateral compression that may result in further compression during each systole
especially under exercise conditions. DB: diagonal branch; LCX: left circumflex ramus; LA: left atrium; LAD: left anterior
descending coronary artery; LM: left main coronary artery; PA: pulmonary artery; RCA: right coronary artery.

further course of 7.9% in mainly symptomatic patients
[22]. De Jonge and co-workers also describe a prevalence
of 7% of CAAs including coronary fistulas [10] in their
patient population. These discrepancies in reported prev-
alence might be caused by referral bias. Some of these
patients with CAAs might have been or were referred
because of known presence of CAA and not because of
unrelated factors as in the general population. In our
study an overall of 17 patients (2.3%) with CAAs were
identified. 41.2% of these patients (n = 7) were already

diagnosed as having CAAs by other imaging modalities,
such as ICA or echocardiography. Excluding these
patients, leads to a prevalence of an anomalous coronary
vessel origination of 1.4% in symptomatic patients. This
result is quite similar to that observed in a large angio-
graphic series [18], as well as in two large previously pub-
lished MDCTA studies dealing either with 4- and 16-slice
CT scanner technology and including 1758 patients [23]
or with 64-slice CT in 1495 patients [24]. However, even
such large studies do not reflect general population as

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-T '_ -
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proximal RCA

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Figure 2
RCA arising from left sinus of Valsalva with a separate ostium (Subgroup 4a). Image A (Volume Rendering Tech-
nique) depicts the whole coronary artery tree. RCA and LM are originating from the left sinus of Valsalva (LSV) with separate
ostia (as shown in Image B, curved Multiplane Reformatting). Again note the ovoid cross-sectional image of the proximal intra-
mural RCA course (left cross-sectional picture of Image A). Additionally, this patient obviously underwent stent implantation
procedure (stent in mid LAD with good contrast enhancement within the stent lumen) due to CHD. Furthermore note the
bright calcified plaque proximal to the previously implanted stent. This severe calcification causes so-called "blurring" impairing
the luminal view. A high grade stenosis therefore cannot be ruled out. Interestingly, proximal LAD and RCA do not show any
additional atherosclerotic plaque formation as depicted in the remaining cross-sectional images. Furthermore small calcified
deposits (spotty calcification) are found at the aortic valve leaflets. LCX: left circumflex ramus; DB: diagonal branch; LAD: left
anterior descending coronary artery; LM: left main coronary artery; LSV: left sinus of Valsalva; PA: pulmonary artery; RCA:
right coronary artery.

only symptomatic patients with indications for either ICA
or MDCTA were considered.

In our study, where roughly the same number of men and
women were initially examined, CAAs appear to be more
common in men (n = 12; 71%) than in women (n = 5;
29%). This was also shown in previous reports [14,25,26],
although such a finding may reflect the selective nature of

referral for cardiac MDCTA. The most common coronary
anomaly in our patient population was an anomalous
RCA arising from the opposite sinus of Valsalva (n = 8;
1.1%), followed by an anomalous origin of the circumflex
ramus (n = 7; 0.9%). These findings are similar to previ-
ously published angiographic studies [11,16,27],
although Wilkins et al [25], as well as Yamanaka et al[ 18],
in the largest angiographic trial including 126,595

patients, report different prevalence in their study popula-
tion. Interestingly, we did not find any split left main cor-
onary artery (Subgroup 1) or a CAA within the aortic root
near proper sinus of Valsalva (Subgroup 2), which might
be explainable by referral bias and presumably lack of
ischemia related symptoms in these specific subgroups as
only symptomatic patients were examined in our popula-
tion. Nevertheless these inconsistent findings concerning
the prevalence of CAA and, moreover, different subgroups
suggest that the described numbers are only true for our
study population. Therefore, a general conclusion for
asymptomatic individuals cannot be drawn.

The clinical impact of CAAs still remains controversial.
Coronary anomalies cause up to 17% of deaths in ath-
letes, and furthermore are associated with 12% of sport-
related deaths in 14- to 40-year-old individuals
[17,28,29]. Furthermore, anomalous origination of a cor-
onary artery from the opposite sinus is related to sudden
death as reported in frequently quoted autopsy reports
[30]. In other anomalies, ischemia occurs only under
inconsistent or extreme clinical conditions. In our study
population, all patients had either chest-pain or previous
history of syncope related to exercise independently of the
type of detected CAA. But out of these findings in a small

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Figure 4
Single coronary artery originating from right sinus of Valsalva (Subgroup 4c). This case shows a single coronary
artery arising from right sinus of Valsalva (common ostium of RCA and LAD without circumflex ramus) in a Maximum Intensity
Projection (Image A). Myocardial territory usually supplied by LCX is fed by RCA (right dominant type) and LAD is noted to
run intra-myocardial within the left ventricular septum (Image B; Curved Multiplane Reformatting). Note the surrounding mus-
cular tissue (also depicted in the cross-sectional image of LAD) marked with black arrows which appears lighter grey compared
to epicardial adipose tissue (white arrow). LAD: left anterior descending coronary artery; LV: left ventricle; RA: right atrium;
RCA: right coronary artery; RSV: right sinus of Valsalva; RV: right ventricle.

symptomatic patient cohort, no conclusion regarding the
malignancy of CAAs in relation to morphological charac-
teristics can be drawn.

Limitations
Although, for screening purposes in order to define the
true prevalence, non-invasive imaging modalities should
be considered and ECG-gated contrast-enhanced MDCTA
has been shown to accurately identify and therefore is
considered to be a reliable method for evaluation of CAAs
[6,31], it also adhere inevitable risks: utilization of ioniz-
ing radiation and the need of iodinate contrast agent

application. In our study estimated mean effective dose
was calculated as 22.35 + 4.62 mSv, which is three to four
times higher than in diagnostic ICA [32]. Therefore,
increasing interest focus on radiation dose reduction
tools, like ECG-controlled tube modulation or prospec-
tively ECG-triggered image acquisition. Initial experiences
raise hope that the use of advanced imaging protocols in
Dual-Source CT or 320-slice CT may lead to reduced radi-
ation exposure [33-35]. Taking into consideration, that
screening for CAAs mainly involves a younger population;
MDCTA to date might not be a useful tool for this purpose
[36]. In this respect, cardiac magnetic resonance tomogra-

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Figure 5
Circumflex ramus originating from right sinus of Valsalva with further posterior vessel course (Subgroup 4d).
This case shows an abnormal origin of LCX from the right sinus of Valsalva with a further posterior (retroaortic) course of
LCX within the atrioventricular groove (Image A, Volume Rendering Technique, posterior view). Cross-sectional curved Mul-
tiplane Reformats nicely depict the anatomic relationships of the vessel, left atrium and Aorta (Images B). In Image B2 the ret-
roaortic course within the atrioventricular groove of LCX is marked with a black arrow. LCX: left circumflex ramus; LA: left
atrium; LAD: left anterior descending coronary artery; LVOT: left ventricular outflow tract; RCA: right coronary artery; RSV:
right sinus of Valsalva.

phy (CMR) which offers excellent diagnostic accuracies
compared to ICA, should be considered as an alternative
test [6].

Additionally, the results of our study were derived by a
symptomatic patient cohort with indications for MDCTA
in a single center study, so that our results are also biased
by referral and do not reflect a general population. Fur-
thermore, this study consisted of 748 patients in which no
Subgroup 1- and Subgroup 2-CAA were found suggesting
that the study population, although only CAAs of origin
and further vessel course were observed is too small.

Conclusions
This study applies a strict classification scheme for detect-
ing CAAs of origin and further vessel course in a sympto-
matic consecutive patient population utilizing cardiac 64-
slice MDCTA and supports the use of CT technology for
the identification and definition of CAA. Prevalence of
these CAAs was similar to large angiographic studies.
However, our study population does not represent a gen-
eral population. But for screening purpose in asympto-
matic patients other imaging modalities, such as CMR
should be considered.

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Competing interests
The authors declare that they have no competing interests.

Authors' contributions
FvZ is responsible for coordination of the study, statistical
evaluation and manuscript. MP and LM are responsible
for the evaluation of MDCTA data sets. PP performed
MDCTA scanning and helped to draft the manuscript. AL
contributed in conception and design of the study. NW
supervised MDCTA data evaluation and interpretation.
AB is responsible for manuscript review.

Pre-publication history
The pre-publication history for this paper can be accessed
here:

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